docs: 重构 API 文档结构并修正源码准确性

- 重组文档目录结构: 每个模块的概述页移动到模块子目录
- 重命名 index.md 为 main.md
- 修正所有模块文档中的错误:
  - math: FromEuler→FromEulerAngles, TransformDirection 包含缩放, Box 是 OBB, Color::ToRGBA 格式
  - containers: 新增 operator==/!= 文档, 补充 std::hash DJB 算法细节
  - core: 修复 types 链接错误
  - debug: LogLevelToString 返回大写, timestamp 是秒, Profiler 空实现标注, Windows API vs ANSI
  - memory: 修复头文件路径, malloc vs operator new, 新增方法文档
  - resources: 修复 Shader/Texture 链接错误
  - threading: TaskSystem::Wait 空实现标注, ReadWriteLock 重入描述, LambdaTask 链接
- 验证: fix_links.py 确认 0 个断裂引用

docs/api/rhi/d3d12/device/device.md

@@ -0,0 +1,42 @@
+# D3D12Device
+
+**命名空间**: `XCEngine::RHI`
+
+**描述**: DirectX 12 设备实现，继承自 `RHIDevice`。
+
+## 公共方法
+
+### 继承方法
+
+| 方法 | 文档 |
+|------|------|
+| `Initialize` | [详细文档](../../../threading/task-system/initialize.md) |
+| `Shutdown` | [详细文档](../../../threading/task-system/shutdown.md) |
+| `CreateBuffer` | [详细文档](../../device/create-buffer.md) |
+| `CreateTexture` | [详细文档](../../device/create-texture.md) |
+| `CreateSwapChain` | [详细文档](../../device/create-swap-chain.md) |
+| `CreateCommandList` | [详细文档](../../device/create-command-list.md) |
+| `CreateCommandQueue` | [详细文档](../../device/create-command-queue.md) |
+| `CompileShader` | [详细文档](../../device/compile-shader.md) |
+| `CreatePipelineState` | [详细文档](../../device/create-pipeline-state.md) |
+| `CreateFence` | [详细文档](../../device/create-fence.md) |
+| `CreateSampler` | [详细文档](../../device/create-sampler.md) |
+| `GetCapabilities` | [详细文档](../../device/get-capabilities.md) |
+| `GetDeviceInfo` | [详细文档](../../device/get-device-info.md) |
+| `GetNativeDevice` | [详细文档](../../device/get-native-device.md) |
+
+### D3D12 特有方法
+
+| 方法 | 文档 |
+|------|------|
+| `GetDevice` | [详细文档](get-device.md) |
+| `GetFactory` | [详细文档](get-factory.md) |
+| `GetAdapterInfo` | [详细文档](get-adapter-info.md) |
+| `EnumerateAdapters` | [详细文档](enumerate-adapters.md) |
+| `GetDescriptorHandleIncrementSize` | [详细文档](get-descriptor-handle-increment-size.md) |
+| `CheckFeatureSupport` | [详细文档](check-feature-support.md) |
+
+## 相关文档
+
+- [D3D12 后端总览](../overview.md)
+- [RHIDevice](../../device/device.md) - 抽象设备接口